Quote Originally Posted by dancqu
Correction second paragraph: The right angle
metal attachments at the wall MAY be up or down.

Additional comments: If the wall is of some masonry or
of uneven construction an interface may be a good idea;
metal channel or solid, strong, straight , 1x4s. Attach with
lag screws or bolts. Shim those horizontals for plumb and
straight. Each shelf will need the same treatment for top
to bottom precise construction. Of course at least one
shelf is needed. I recommend that level be established
independent of floor or ceiling.

If you luck out all that's needed is top and shelving, two
legs, and attachment hardware. Dan
Here's a simplification although likely more expensive.
At the wall use a single length of right angle steel or
aluminum for top and each shelf. Shim as suggested
in my previous post.

With large heavy enlargers I'd suggest 3/4 inch solid
core plywood; marine if possible. Shelves can be
of lighter weight. Dan